Telephone repeater



June 22, 1926. I

O. B. JACOBS TELEPHONE REPEATER Filed Oct. 18, 1919 I N V EN TOR. Q15? Jacas d mv I. s... 1* g ATTORNEY Patented June 22, 1926.

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My invention relates to repeater circuits. One object of the invention is to eliminate the repeating coils heretofore commonly placed into the side conductors of a phantom group for the purpose of associatlng a repeater with the phantom circuit, these coils being objectionable for the ,reason that they necessitate the addition of impedance devices to the network to correct for the change which is caused by the coils in the impedance of the line. In this invention the apparatus of the phantom repeater is connected to the line conductors at the points or symmetry between the lines and the'side circuit networks,"i. e., at thepoiiits where;

the impedance of the network circuit .is substantially equal to the impedance of the line circuit, which points coincide with the midpoints of the transformers commonly used in the side circuit repeaters. Apparatus associated-with these points causes no sociated with/fthe primary windin change in the relative values of the impedances of the network and hne circuits, and therefore no unbalance.

Another object of the invention is to as-" sociate with the said other apparatus hereto ore so connected to the line wires as to cause an unbalance between the network and the line, for example the apparatus employed for shunting or relaying signaling currents (low frequency al'- ternating or; direct) around the repeater installation. v Various other featuresand objects of the invention will appear description thereof, the accompanying drawing showing in diagrammatic view one form and arrangement of apparatus embodying the invention.

In this drawing, reference characters; 1 and 2 designate the line conductors of one s1de of a phantom group'and numerals 1 and 2", the conductors of the Conductors 1 and 2 ate divided into east and west sections terminated by balancing networks N, which-sec ions are associated for 'currents'of voice frequencies by-means of a two-element twp-way repeater of a type we known in the art{ this repeater comprisin transformers 9, he midpoints 7 and 8 0 which are associated-by means of transformers 6 with devices 5,theo11tput;circuits of whic are asof the aforementioned transformers 9. e opera-.

oints of symmetry from the following a reference being, had 'to' other side of the group.

L'extending 'stantially ll tending east thereof. The phantom repeatering currents from one section 0 tion of the repeater is well understood and 1s briefly as follows: A portion of the voi'ce currents in the west'section of conductors .1- and 2-enters transformer 6 and is impressed thereby on the amplifying" device 6' which augments the value of t current and 1mpre$es the amplified current -on transformer 9, which causes the current toenter the east sectionof the line. The operation of the repeater from eastto west is similar. I

The conductors 1" and 2 areprovided with a similar repeater, the parts of which are designated in the drawing by like char- ,acters of reference; a prime mark being used to distmgu' 'ish this a aratus from that of conductors 1 and 2; P

The phantom repeater, comprised of transformers 34 and amplifying devices 32, is similar to the side circuit repeaters hereinbefore described It is associated with the line conductors by means of connections 30 and 31 to the midpoints of the rimary windings'of the transformers 6 an 6', re-

spectively.' It operates by causing phantom current in conductors 1 and 2 to flow through transformer 6 in op to directions and enter conductors 30, m which conductor the current traverse the windings of trans- ,former 34 and network N and returns throu h conductor 31' and the windin of trans ormer 6' to conductors 1' and 2'. The

input circuit'of the amplifying device 82 shunts a portion of this current and causes amplified current to now through transformer 34 into the east section of the phantom circuit. The operation of the repeater from east to west is similar and need not be p 7 se arately explained.

is thus connected throng transformers 6 and 6', to the transformer midpoints 7, 8' and 7', 8', at which points there exists symmetry between the line circuits and the network circuits, the impedance of the circuit west of these points being subequal to that of the circuit exa paratus thus causes no unbalance between t e networks and their respective sectiens of the line, and additionalimpedances are not the balance; I v

For the purpose of conducti the signalas apparatus of thehantom repeater the input sides of amplifying required in the networks for maintaining.

the'line to no the other, I provide connections 15 and 16 between points 7, 8, 7 'and 8 of the east and west sections respectively, of the line. The connections are provided with inductance coils 17 to prevent the flow therethrough of the high frequency alternating voice currents, and with condensers 18 connected to ground to shunt out such alternating currents as traverse coils 17, series condensers 19 and shunt inductance coils 20 being employed to prevent the flow of the direct and there are provided telegraph keys 40 .for

sending telegraphic messages over the conductors 1' of the left and right sections of the line respectively. This arrangement is merely illustrative, it being readily understood that any other suitable apparatus may be associated with any of the line wires in the manner herein shown.

Although only one form and arrangement of apparatus embodying this invention is shown and. described herein, it is readily understood that various changes and modifications may be made therein within the scope of the following claims, without departing from the spirit and scope of this invention. 7

What is claimed is: Y

1. In combination, a transmission line having phantom and'side circuits, each in two sections, balancing networks for said side circuit sections, a phantom repeater associ ated with the line at the points of symmetry between the line sections and the networks, and a direct current path connecting the sections between the same points.

2. In combination, a transmission line having phantom andside circuits, each side circuit having two conductors, balancing networks for said side circuits, a phantom repeater associated with the line at the points of symmetry between the line and the networks, and lOW. frequency through bilaterally conductive signaling paths connecting these points of symmetry for respective pairs of conductors.

In testimony whereof, I have signed my name to this specification this 17th day of October 1919.

OLIVER B. JACOBS. 

